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Abstract:

A PCRF node (120) for a communications system, equipped with an interface
(Gx) towards a PCEF node (130), in the system. The PCRF node (120) is
arranged to use said interface to provide the PCEF node (130) with new or
updated PCC rules for a User Equipment. The PCRF node (120) is also
equipped with an interface (Sy) towards an OCS node (115), and is
arranged to as a result of a trigger signal, request a credit indication
for the new or updated PCC rules for the User Equipment from the OCS node
(115) over the interface to the OCS node (115), to receive a credit
indication for the new or updated PCC rules for the User Equipment from
the OCS node (115) over the interface (Sy) to the OCS node, and to
provide said credit information to the PCEF node (130). An OCS node (115)
is also disclosed.

Claims:

1. A Policy and Charging Rules Function node, PCRF node (120), for a
communications system (100), the PCRF node (120) being equipped to use a
first interface (Gx) to communicate with a Policy and Charging
Enforcement Function node, PCEF node (130), in the communications system
(100), the PCRF node (120) being arranged to use said first interface
(Gx) to provide the PCEF node (130) with one of new and updated Policy
and Charging Control, PCC, rules for a User Equipment (140) in the
communication system (100), the PCRF node (120) being equipped to use a
second interface (Sy) to communicate with an Online Charging System node,
an OCS node (115), in the communications system, and in that the PCRF
node (120) is arranged to: as a result of a trigger signal which is one
of internal and external to the PCRF node (120), request a credit
indication for one of new and updated PCC rules for the User Equipment
from the OCS node (115) over the second interface (Sy) as a result of
said request, receive a credit indication of one of new and updated PCC
rules for the User Equipment from the OCS node (115) over the second
interface (Sy); and to provide said credit indication to the PCEF node
(130) over the first interface (Gx).

2. The PCRF node (120) of claim 1, the PCRF node (120) being arranged to
provide the credit indication to the PCEF node (130) in a charging policy
decision which the PCRF node (120) transmits to the PCEF node (130).

3. The PCRF node (120) of claim 1, in which the internal trigger signal
is a timer.

4. The PCRF node (120) of claim 1, in which the external trigger signal
is at least one of: a session activation request from the User Equipment
(140), a session modification for the User Equipment (140), a request for
one of a new and changed service for the User Equipment (140), and a
received update of subscription data corresponding to the User Equipment
(140).

5. The PCRF node (120) of claim 1, the PCRF node (120) being arranged to
request the credit indication per one of service, group of services and
rating group used by the User Equipment (140).

6. The PCRF node (120) of claim 1, in which the second interface is
different from a 3GPP Gx interface and 3GPP Gy interface.

7. The PCRF node (120) of claim 1, in which the first interface is a 3GPP
Gx interface.

8. An Online Charging System node, OCS node (115), in a communications
system, the OCS node (115) being equipped to use an interface to
communicate with a Policy and Charging Rules Function node, PCRF node
(120), the OCS node (115) being arranged to receive a request for a
credit indication for one of a service, group of services and rating
group associated with at least one Policy and Charging Control rules, PCC
rules, for a User Equipment (140) from the PCRF node (120) over the
interface, and, as a result of said request, to transmit the credit
indication for the one of the service, group of services and rating
groups for the User Equipment (140) to the PCRF node (120) over the
interface.

9. The OCS node (115) of claim 8, in which the interface is different
from a 3GPP Gx interface and 3GPP Gy interface.

10. A Policy and Charging Enforcement node, PCEF node (130), for a
communications system (100), the PCEF node (130) being equipped to use a
first interface (Gx) to communicate with a Policy and Charging Rules
node, PCRF node (120), and to use a second interface (Gy) to communicate
with an Online Charging System node, OCS node (115), the PCEF node (130)
being arranged to receive rules for Policy and Charging Control, PCC
rules, for a User Equipment (140) in the communications system (100) from
the PCRF node (120) over the first interface (Gx), the PCEF node (130)
being arranged to, if the PCC rules for the User Equipment (140) contain
a credit indication that indicate that the User Equipment (140) has
sufficient credit to utilize at least one of a service and services
associated with the credit, wait for the User Equipment (140) to start
utilizing the system, and when that happens, to establish a session with
the OCS node over the second interface (Gy), and if the PCC rules
received from the PCRF node (120) contain a credit indication that
indicate that the User Equipment (140) lacks sufficient credit to utilize
the services associated with the credit, to establish a session with the
OCS node (115) over the second interface (Gy) and await a decision from
the OCS node regarding actions to be taken with traffic from the User
Equipment (140).

11. The PCEF node (130) of claim 10, in which the first interface is a
3GPP Gx interface.

12. The PCEF node (130) of claim 10, in which the second interface is a
3GPP Gy interface.

13. The PCRF node (120) of claim 2, in which the external trigger signal
is at least one of: a session activation request from the User Equipment
(140); a session modification for the User Equipment (140); a request for
one of a new and changed service for the User Equipment (140); and a
received update of subscription data corresponding to the User Equipment
(140).

14. The PCRF node (120) of claim 2, the PCRF node (120) being arranged to
request the credit indication per one of service, group of services and
rating group used by the User Equipment (140).

15. The PCRF node (120) of claim 14, in which the second interface is
different from a 3GPP Gx interface and 3GPP Gy interface.

16. The PCRF node (120) of claim 15, in which the first interface is a
3GPP Gx interface.

17. The PCRF node (120) of claim 16, in which the internal trigger signal
is a timer.

18. The PCRF node (120) of claim 1, in which the external trigger signal
is one of a session modification for the User Equipment (140) and
received update of subscription data corresponding to the User Equipment
(140).

19. The PCRF node (120) of claim 18, in which the second interface is
different from a 3GPP Gx interface and 3GPP Gy interface.

20. The PCEF node (130) of claim 11, in which the second interface to the
OCS node (115) is a 3GPP Gy interface.

Description:

[0002] The Policy and Charging Control, PCC, architecture was introduced
in 3GPP Rel-7 and has been further evolved in 3GPP Rel8 and Rel9. It
provides operators with advanced tools for service-aware QoS and charging
control.

[0003] For 3GPP Rel-10, there is currently a Study Item for Policy
Enhancements that investigates various functional additions to the
already existing architecture. Currently there are 4 key issues under
investigation. One of those key issues is called "QoS and gating control
based on spending limits". This key issues looks into the case when the
QoS (bandwidth) of an ongoing session must be throttled due to the fact
that the user has reached some form of credit related limit. One example
might be that the user is roaming (data services while roaming is often
expensive and charged per Megabyte) and has a pre-defined safety limit of
e.g. 50 Euros when the bandwidth should be set to a minimum until the
user has been informed and once again agreed to be charged for another 50
Euros.

[0004] In the current PCC architecture, when a new PDN-connection is set
up or when it is being modified, the PCEF (i.e. PDN-GW or GGSN) always
queries the PCRF over the Gx interface, i.e. the interface between PCEF
and PCRF, for a policy decision prior to requesting credit from the OCS
over the Gy interface, i.e. the interface between PCEF and OCS. There are
two alternatives defined for when credit requests over the Gy interface
may take place according to the present 3GPP standard. One alternative is
to request credits from the OCS over the Gy interface immediately at
PDN-connection establishment, and another alternative is to delay the
request of credit until an incoming payload packet is classified by the
PCEF to an authorized service for which online charging applies.

SUMMARY

[0005] It is a purpose of the present invention to provide a solution
which will provide improvements to the procedure which is used at present
when a new PDN-connection is set up or when an existing PDN connection is
modified.

[0006] This purpose is addressed by the present invention in that it
discloses a Policy and Charging Rules Function node, a PCRF node, for a
communications system. The PCRF node of the invention is equipped with an
interface towards a Policy and Charging Enforcement Function node, a PCEF
node, in the communications system and is arranged to use this interface
to provide the PCEF node with new or updated Policy and Charging Control,
PCC, rules for an end user, here referred to as a User Equipment,
abbreviated as UE, in the communications system.

[0007] According to the invention, the PCRF node is also equipped with an
interface towards an Online Charging System node, an OCS node, in the
communications system, and is also arranged to: [0008] As a result of a
trigger signal which is internal or external to the PCRF node, request a
credit indication for the new or updated PCC rules for the UE from the
OCS node over the interface to the OCS node, [0009] As a result of the
request, receive a credit indication for the new or updated PCC rules for
the UE from the OCS node over the interface to the OCS node, [0010] To
provide the credit information to the PCEF node over the interface to the
PCEF node.

[0011] In some embodiments, the PCRF node of the invention is arranged to
provide the credit information to the PCEF node in a charging policy
decision which the PCRF node transmits to the PCEF node.

[0012] In some embodiments of the PCRF node of the invention, the internal
trigger signal is a timer.

[0013] In one embodiment in the PCRF node of the invention, the external
trigger signal is one or more of the following: [0014] a session
activation request from the UE, [0015] a session modification for the UE,
[0016] a request for a new or changed service for the UE, [0017] a
received update in the UE's subscription data.

[0018] In some embodiments, the PCRF node of the invention is arranged to
request the credit indication per service, group of services or per
rating group used by the UE.

[0019] In one embodiment of the PCRF node of the invention, the interface
towards the OCS node is the Sy interface.

[0020] In one embodiment of the PCRF node of the invention, the interface
towards the PCEF node is the 3GPP Gx interface.

[0021] The invention also discloses an Online Charging System node, an OCS
node, in a communications system.

[0022] The OCS node is equipped with an interface towards a Policy and
Charging Rules Function node, a PCRF node, and the OCS node is arranged
to receive a request for a credit indication for a service, group of
services or rating group associated with one or more Policy and Charging
Control rules, PCC rules, for a User Equipment from the PCRF node over
the interface to the PCRF node, and, as a result of said request, to
transmit a credit indication for the service, group of services or rating
groups for the User Equipment to the PCRF node over the interface to the
PCRF node.

[0023] In some embodiments of the OCS node, the interface to the PCRF node
is the Sy interface.

[0024] In addition, the invention also discloses a Policy and Charging
Enforcement node, a PCEF node, for a communications system. The PCEF node
is equipped with an interface towards a Policy and Charging Rules node, a
PCRF node, and with an interface towards an Online Charging System node,
an OCS node.

[0025] The PCEF node is arranged to receive rules for Policy and Charging
Control, PCC rules, for a User Equipment in the communications system
from the PCRF node over the Gx interface. The PCEF node is arranged to,
if the PCC rules for the UE contain a credit indication that indicate
that the UE has sufficient credit to utilize the service or services
associated with the credit, wait for the UE to start utilizing the
system, and when that happens, to establish a session with the OCS node
over the interface to that node. If the PCC rules received from the PCRF
node contain a credit indication that indicate that the UE doesn't have
sufficient credit to utilize the service or services associated with the
credit, the PCEF node is arranged to establish a session with the OCS
node over the Gy interface and await a decision from the OCS node
regarding actions to be taken with traffic from the UE.

[0026] In some embodiments of the PCEF node, the interface to the PCRF
node is the 3GPP Gx interface.

[0027] In some embodiments of the PCEF node, the interface to the OCS node
is the 3GPP Gy interface.

BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The invention will be described in more detail in the following,
with reference to the appended drawings, in which

[0029]FIG. 1 shows an overview of a system in which the invention is
applied, and

[0030] FIGS. 2 and 3 show event diagrams in a system in which the
invention is used.

DETAILED DESCRIPTION

[0031]FIG. 1 shows an overview of a communications system 100 in which
the invention is applied. The invention will be described by means of the
system 100 in FIG. 1, using terminology which is taken from the 3GPP
project. It should however be emphasized that the invention is also
applicable within systems which are "wire bound", i.e. system which use
landlines.

[0040] As is also shown in FIG. 1, in the system 100 there are interfaces
between some of the nodes or components. Thus, between the PCEF 130 and
the PCRF 120 there is the so called Gx interface, and between the PCEF
130 and the OCS 115, there is the so called Gy interface. These
interfaces are known to those skilled in the art and will therefore not
be described in further detail here.

[0041] The present invention proposes opening up an interface between the
OCS 115 and the PCRF 120, in addition to the existing interfaces in the
system 100. The proposed interface (sometimes also referred to as a
"reference point") between the OCS 115 and the PCRF 120 is labeled Sy
interface, and is shown in bold lines in FIG. 1, in order to facilitate
for the reader.

[0042] One purpose of introducing the Sy interface is to address the case
sometimes known as "QoS and gating control based on spending limits".
This case occurs when the QoS (Quality of Service, e.g. bandwidth) of an
ongoing session must be "throttled" due to the fact that the user has
reached some form of credit related limit. One example might be that the
user is roaming (data services while roaming is often expensive and
charged per Megabyte) and has a pre-defined safety or billing limit of
e.g. 50 Euros. In such cases, it might be advantageous to set the
bandwidth to a minimum e.g. until the user has been informed that the
credit limit has been reached and has agreed to be charged for another 50
Euros, or until a certain payment period, such as, for example, the
present month, has ended.

[0043] In some embodiments of the present invention, the Sy interface will
be initiated by the PCRF 120 at an IP-CAN session establishment for the
UE 140 and will be used to transfer charging related information from the
OCS 115 to the PCRF 120. Based on this information, the PCRF 120 can then
make policy decision, such as e.g. altering the QoS of the user. Possible
other use cases of the Sy interface include: [0044] Notification that
the UE is out of credit; [0045] Notification that the UE is not out of
credit; [0046] Notification that the UE is currently "promoted", i.e. has
a certain status within the operator's network, such as e.g. "gold
client"; [0047] Notification that the UE has reached a certain credit
threshold (e.g. 50 Euros).

[0048] As stated previously, it is a purpose of the present invention to
provide a solution which will provide improvements to the procedure which
is used at present when a new PDN connection is set up or when an
existing PDN connection is modified. To this end, by means of the
introduction of the Sy interface, the PCRF 120 will be able to get an
early credit indication from the OCS 115, possibly per service, or group
of services or per so called rating group. The PCRF 120 can then indicate
this over the Gx interface to the PCEF, which for example can be a PGW,
PDN Gateway, or a GGSN, or will be embodied in such nodes. With this
information, the PCEF 130 can safely allow traffic to flow for all
associated services, group of services or rating groups for which the
PCRF has indicated that credit is available during the time of the credit
request over Gy. This would greatly reduce the procedures associated with
"QoS and gating control based on spending limits". In addition, the PCEF
could in an initial request over the Gx to the PCRF request early credit
indications to be provided, or the PCRF could request over Sy that the
OCS notifies the PCRF in case the user's account becomes empty or
refilled, possibly per service, group of services or per rating group. In
addition, the PCRF could notify the PCEF over the Gx interface in the
case that there is a change in previously provided credit indications,
possibly per service, group of services or per rating group.

[0049] The invention also discloses an improved PCEF node 130. The PCEF
node 130 is, as shown in FIG. 1 and as mentioned above, equipped with a
Gx interface towards the PCRF node 120, and with a Gy interface towards
the Online Charging System node, the OCS node 115. The PCEF node 130 is
arranged to receive rules for Policy and Charging Control, PCC rules, for
a UE 140 in the communications system 100 from the PCRF node 120 over the
Gx interface. As disclosed by the invention, the PCEF node 130 is
arranged to, if the PCC rules for the UE 140 contain a credit indication
that indicate that the UE has sufficient credit to utilize the service or
services associated with the credit, wait for the UE 140 to start
utilizing the system, and when that happens, to establish a session with
the OCS node over the Gy interface to the OCS node. If, on the other
hand, the PCC rules received from the PCRF node 120 contain a credit
indication that indicate that the UE 140 doesn't have sufficient credit
to utilize the services associated with the credit, the PCEF node 130 is
arranged to establish a session with the OCS node 115 over the Gy
interface to the OCS node and to await a decision from the OCS node
regarding actions to be taken with traffic from the UE 140.

[0050] An example of an event sequence in a system in which the present
invention is applied will now be given with reference to FIG. 2, which
shows events and messages sent between the nodes PCEF 130, OCS 115 and
PCRF 120 in the system 100 of FIG. 1. Events 1-3 have been framed with
dashed lines in order to indicate that these are the events in FIG. 2
which are primarily related to the present invention.

[0051] The events and messages of FIG. 2 have been numbered sequentially,
and are as follows: [0052] 1. The PCRF decides to install a new or
modified PCC rules in the PCEF. The decision is triggered either by an
event external or internal to the PCRF. Examples of internal such events
are timers, and examples of external such events are one or more of the
following: [0053] a session activation request from the UE, [0054] a
session modification for the UE, [0055] a request for a new or changed
service for the UE, [0056] a received update in the UE's subscription
data. [0057] an update in the user's subscription from the SPR, Note
that for the case of a session activation request, such as for example,
an IP-CAN Session Establishment, the PCEF may have specifically requested
an early credit indication from the PCRF. [0058] 2. The PCRF issues a
request to the OCS over the Sy interface and requests an early credit
indication for the new or modified service(s). [0059] 3. The OCS responds
over the Sy interface with the requested credit indicator(s). [0060] 4.
The PCRF formulates a policy decision and provides this decision to the
PCEF. The policy decision also includes the credit indication (possibly
per service, group of services, PCC rule or per rating group). [0061] 5.
The PCEF acknowledges the policy decision message. [0062] 6. Because of
the credit indicator(s), the PCEF knows if the account of the end user is
empty or not and therefore, in case the account is not empty i.e. the
credit indication(s) was positive, does not have to request credits for
the associated rating groups and/or services immediately. Potential
bearer or session related signaling may take place as specified in 3GPP
TS 23.203. [0063] 7. At a later point in time, an incoming payload packet
from the UE (i.e. uplink) or from an external network (i.e. downlink) is
classified by the PCEF to an authorized service for which online charging
applies, but where the credit request has been delayed due to a positive
credit indication received in step 4. The payload is allowed to flow, but
the PCEF immediately starts to measure the traffic (in time, volume or
service specific units). [0064] 8. Step 7 triggers the PCEF to perform a
credit request for the associated service or rating group. [0065] 9.
Credit is granted by the OCS. The PCEF deducts the measured amount of
credits that has already been consumed since step 7.

[0066] Another example of an event sequence in a system in which the
present invention is applied will now be given with reference to FIG. 3,
which shows events and messages sent between the nodes PCEF 130, OCS 115
and PCRF 120 in the system 100 of FIG. 1. Events 2 and 3 have been framed
with dashed lines in order to indicate that these are the events in FIG.
3 which are primarily related to the present invention.

[0067] The events and messages of FIG. 3 have been numbered sequentially,
and are as follows: [0068] 1. In the OCS, the account status of a UE is
changed beyond a certain threshold limit. This may e.g. happen because
the account is refilled or because the value of the account is exhausted.
[0069] 2. The OCS transmits a Credit Report Update to the PCRF. [0070] 3.
The PCRF transmits an acknowledgment, ACK, of this to the OCS. [0071] 4.
The PCRF establishes a new condition for the user of the account in
question. [0072] 5. The PCRF transmits the Policy Decision Update to the
PCEF, for example as new or updated credit indicators. [0073] 6. The PCEF
transmits an acknowledgment, ACK, of this to the PCRF.

[0074] The invention is not limited to the examples of embodiments
described above and shown in the drawings, but may be freely varied
within the scope of the appended claims.